Measuring pressure in a fuel-flexible Micro Gas Turbine
Unlike conventional electric vehicles that rely solely on batteries, the team's concept generates electrical power by combusting sustainable fuels in a specially designed combustion chamber. The generated hot gases drive a turbine that powers a generator, creating a compact range-extending power source that can operate on multiple renewable fuels.
High-temperature pressure measurement for sustainable power generation
To validate the performance of this system, accurate pressure measurements at elevated temperatures were essential. Althen Sensors & Controls supplied high-temperature pressure sensors equipped with temperature isolators, enabling reliable pressure measurements in locations where conventional pressure sensors could not be used safely.
Generating electrical power from sustainable fuels
Eco-Runner Team Delft is one of Delft University of Technology's renowned Dream Teams, consisting of students from multiple engineering disciplines. Each team spends one academic year designing, developing and validating a new sustainable mobility concept.
The XVI team set itself the ambitious goal of demonstrating a practical fuel-flexible Micro Gas Turbine capable of efficiently generating electrical power from sustainable fuels. Achieving this required the design of an entirely new combustion chamber and turbine system that could withstand extremely demanding operating conditions.
Understanding pressure behaviour
During development, understanding the pressure behaviour throughout the system became critical. Standard pressure sensors are generally unsuitable for direct installation near high-temperature combustion processes. The project therefore required sensors that could accurately measure pressure while remaining protected from the extreme thermal environment. Althen's pressure sensor with an integrated temperature isolator provided the required solution.
Challenge and measurement requirements
The development team needed accurate pressure measurements to determine:
- the compressor pressure ratio;
- the pressure drop across the turbine;
- combustion efficiency;
- overall system performance;
- fuel-air ratio optimisation;
- validation of simulation models.
Combined with temperature and mass flow measurements, the pressure data allowed the engineers to analyse thermodynamic efficiency and compare real-world results with their design calculations.
The collected measurement data also served as an important basis for future design improvements of both the combustion chamber and the Micro Gas Turbine.
High-temperature pressure sensors
Althen supplied two AHI2200 high-temperature pressure sensors, each combined with a temperature isolator.
The AHI2200 is based on Silicon-on-Sapphire sensor technology and is designed for accurate pressure measurement in demanding high-temperature environments. The sensor has an accuracy of 0.1% and can operate at ambient and media temperatures of up to 200 °C.
The temperature isolators provided additional thermal protection between the hot gas system and the pressure sensors. This allowed the sensors to be installed close to the combustion process while reducing their direct exposure to the highest temperatures.
The two sensors were used to measure pressure at separate points in the Micro Gas Turbine:
- downstream of the combustion chamber;
- directly downstream of the turbine.
By comparing the measurements at these locations with the pressure measured elsewhere in the system, the team could determine the compressor pressure ratio and the pressure drop across the turbine.
Implementation
The sensors were integrated into the Micro Gas Turbine test setup during system development. Pressure measurements were continuously combined with temperature and mass flow data to evaluate:
- compressor performance;
- turbine efficiency;
- combustion performance;
- overall system behaviour.
The measured values were compared with simulations and engineering calculations throughout the development process, allowing the team to verify the performance of their combustion chamber design.
Stable and reliable pressure measurements
The pressure sensors performed exactly as expected throughout the testing programme. Despite the demanding operating conditions and elevated temperatures, the sensors delivered stable and reliable pressure measurements that closely matched the predicted simulation results. Using the collected data, Eco-Runner Team Delft successfully validated the performance of their combustion chamber and confirmed that the overall system behaved according to the intended design.
The validated pressure measurements became an important step in the further development of the Micro Gas Turbine, ultimately enabling the team to successfully generate electricity using a fuel-flexible combustion system.
"Working with Althen was fast, straightforward and highly professional. From the very first contact, their engineers actively helped us think through our measurement challenge and quickly identified a suitable solution. Communication throughout the project was clear, efficient and practical. Their willingness to focus on what was technically possible rather than only on standard solutions made the collaboration particularly valuable for our team."
Althen's contribution
By supplying high-temperature pressure sensors with temperature isolation, Althen enabled accurate pressure measurements in one of the most demanding parts of the Micro Gas Turbine.
The combination of suitable sensor technology, engineering support and practical application knowledge helped Eco-Runner Team Delft obtain the measurement data required to validate their innovative fuel-flexible power generation concept.
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